Questions tagged [fibre-channel]

Fibre-channel is a communications protocol widely used in storage networks. It's most widely deployed in enterprise SAN environments, where large amounts of storage need to be shared amongst a number of different hosts, potentially over longer distances. The protocol is primarily used over fibre optic media (hence the name), but can also be used with copper interconnects.

Fibre channel is a communications protocol widely used in storage area networks (SANs).

The protocol itself is used to communicate storage commands and data flow (typically SCSI) between a particular storage controller and a host to which the storage is exposed. It has a number of different speed variants, most commonly seen are 2G, 4G and 8G with bandwidth limitations of 2Gbit, 4Gbit and 8Gbit respectively. 16Gbit has recently been introduced.

A fibre channel network can have a number of topologies. This can be a loop (called FCAL - Fibre Channel Arbitrated Loop) where a single host bus adaptor is connected to a single loop with one or more devices on it. FCAL is normally used to connect a controller to a disk array as fibre channel disks typically don't directly support switched fabrics.

A fabric is a switched network using one or more switches to connect hosts to controllers1 in a M:M relationship. Fibre channel supports multiple paths between hosts and controllers, and fibre channel disks actually support two loop interfaces through a SCA-40 plug. This allows the implementation of architectures with no single point of failure. Controller pairs can synchronise caches and a host with multi-pathing support can use both controllers in a pair or fail over from one to the other.

Fibre channel is most widely deployed in enterprise SAN environments where a large amount of storage must be shared amongst different hosts. Single mode fibre connections allow storage area networks to cover campus or metropolitan areas tens of kilometres. Replication over wider areas typically requires the controllers to be connected through another WAN protocol such as ATM.

Native Fibre Channel can be run over copper or fibre optic interconnects, although a protocol known as Fibre Channel Over Ethernet (FCoE) encodes the payload over Ethernet frames, allowing the use of cheaper Ethernet cabling and switches.

1 A controller is something like a SAN controller that presents one or more volumes to the SAN through Logical Unit Numbers (LUNs). A SAN can have more than one controller.

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Fibre channel long distance woes

I need a fresh pair of eyes. We're using a 15km fibre optic line across which fibrechannel and 10GbE is multiplexed (passive optical CWDM). For FC we have long distance lasers suitable up to 40km (Skylane SFCxx0404F0D). The multiplexer is limited by…
Marki
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How should I set up my Fibre Channel (FC) network?

How do FC switches work, and how should I configure mine?
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Checking fiber cables for light without risking my eyes

I do storage, so I do a lot of fiber. I am also unlucky enough to have a patch panel with single strands, so when someone else does patching for me, it's usually a mystery which of the two strands I'm holding will end up being the tx (send) and…
Basil
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Can you connect a SAN directly to a HBA with Fibre Channel?

I am in the process of sourcing our company's first SAN as we have the need for high availability/shared storage. I have noticed fibre channel switches are extremely expensive, and for redundancy we will require 2 of them, costing around $12000 on…
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Correct placement of devices on a Fibre Channel fabric

We're getting a pair of new 8Gb switches for our fibre channel fabric. This is a Good Thing since we're running out of ports in our primary datacenter, and it'll allow us to have at least one 8Gb ISL running between our two datacenters. Our two…
sysadmin1138
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Fibre Channel LUN rescan and QLogic

I have a serious problem with a SAN storage array connected to a Linux box through Fibre Channel. Here is the configuration : Debian with plain vanilla linux 2.6.27.25 Fibre controller QLogic 4Gb dual port ( ISP2432 based) Basically the problem…
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How Fibre Channel Frames are populated and traverse a Fabric?

Trying to wrap my head around how Fibre Channel Frames are actually populated and sent through a switched fabric. I Understand WWNN WWPN, WWNN is a WWN of the actual HBA, and WWPN are the WWN of the actually ports on the card. So if a HBA has 4…
Jim
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Cheap but Highly Available Shared Storage?

my group is in the market for plentiful storage. We traditionally used big-iron FC-attached SANs, but they are way expensive and provide much more performance than we require. We want highly available shared storage, and if it performs like local…
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Can I dynamically expose an entire SCSI host over Fibre Channel, preferably in Linux

Is it possible to expose an entire SCSI host dynamically (an LSI HBA or RAID card) over Fibre Channel, if so how? Preferably on Linux (perhaps targetcli) and with disk hotplugging support. (i.e. unplug/replug a disk in the target and the initiator…
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VMWare ESX and guest settings for Netapp cluster failover

If I'm running VMWare 5.x on FC [edit] LUNs presented from a Netapp running ontap 8.x in 7 mode, what steps should I take to ensure that the VMs can withstand a worst possible case cluster node failover? HBA settings? ESX settings? Modifications to…
Basil
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FCoE, on any Ethernet switch?

I understand the concept of FCoE. I have looked at the Wikipedia page and looking at the layer 2 frame diagram, it looks like FCoE really should "just work" on any Ethernet switch, but is this really the case? If so, what do switches like Cisco's…
jwbensley
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Which events specifically cause Windows 2008 to mark a SAN volume offline?

I am searching for specific criteria/events that will cause Windows 2008 to mark a SAN volume as offline in disk management, even though it is connected to that SAN volume via FC or iSCSI. Microsoft states that "A dynamic disk may become Offline if…
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Is 10Gbps fiber (aqua or teal clad) backwards compatible with 4Gbps/8Gbps (normally orange clad fiber) FC equipment?

Just like the subject says. I've got a mess of FC hardware in a rack that I'd like to replace the cabling on. Looking at Monoprice I see that LC/LC cables are really close in price between 10Gb and "normal" ($9.18 for a 1m 10Gb, $8.91 for a 1m…
Bill Weiss
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Fibre channel zoning by port: bad idea?

I have a single FC switch here that has a bunch of servers hanging off of it. Currently it is zoned (as per my previous question, Fibre Channel zoning best practices) by WWN, one zone for each pair of (server, disk array). My question is, is there…
Bill Weiss
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Rough estimate for speed advantage of SAN-via-fibre to san-via-iSCSI when using VMware vSphere

We are in the process of setting up two virtualization servers (DELL R710, Dual Quadcore Xeon CPUs at 2.3 Ghz, 48 GB RAM) for VMware VSphere with storage on a SAN (DELL Powervault MD3000i, 10x 500 GB SAS drives, RAID 5) which will be attached via…
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